Bill Cheek - World Scanner Report

REFERENCE DATA

WSR Voice/Business, l:30pm-5:30pm, PDT

Non-holiday weekdays ONLY,\,.,(619) 578-9247

Hertzian Intercept BBS, 5 :30pm- 1:30pm, PDT
Weekdays & 24-hrs weeken<te...(619) 578-9247
BBS Setup: 12Q0~28 f 80(M>ps, 8N1, ANSI or TTY.

Index & Table of Contents to WSR always available
for free download from BBS or $5 for MS-DOS
floppy disk or $5 printed hard copy.

NEW FEATURE COMING!

I think it’s about time to do some
elementary circuit analysis starting this
month and continuing in the issues
ahead. There are many slick and wicked
circuits in the current crop of scanners
on the market and if you know how they
work, it might help you become a better
hacker. At the least, you might be able
to “copy” or emulate some of these
circuits for your own hacking and
experimenting needs around shop and
shack. This month, we’re going to take
a close look at the Low Battery Warning
and Memory Retention circuits in the
venerable PRO-2004/5/6 scanners.

Each month, I’ll try to dissect and
explain a new circuit from these and
other scanners. Your preferences are
very important, so if you have a pet
peeve or favored circuit that you’d like to
better understand, just let me know so I
can put it on the list This offer is pretty
much limited to scanners for which I
have Service Manuals on file. If I don’t
have the manual, you’ll be expected to
provide it, else do without the analysis.
Use postal mail, e-mail, fax, or the
Hertzian Intercept BBS to get your
request on the list. You can also register
it by voice phone with Cindy during our
normal voice phone hours, if you like.

PRO-2004/5/6

LOW BATT CIRCUIT

EXPMINEL )

The Low Battery Warning indicator in the
PRO-2004/5/6 is a work of art, and just
complicated and mysterious enough to
confuse many wannabe hackers. It also
screams for a little improvement here
and there, so let’s take a detailed look at
the meat 'n taters of this circuit and see
what can be done with it. It’s pretty slick
and yet easily understood with just a little
guidance. See the above drawing of the
Low Battery Indicator circuit for the PRO-
2005/6 which is identical to that of the
PRQ-2004 except for circuit symbols.

WORLD SCANNER REPORT

A Journal of VHF-UHF Radio Technology & Engineering

Published by COMMtronics Engineering at PO Box 262478; San Diego* CA 92196

Publisher/Editor: W. D. Cheek, Sr* a.k»a+ "Dr. Rigormortis n
Copyright © 1991-95 <A11 Rights Reseired> ISSN 1061-9240

Volume 5, Number 2 $5.00

PRO-2005/6 LOW BATT WARNING CIRCUIT

(Identical for PRO-2004 though circuit symbols may differ)

8.3v Supply

A

R-234

470-k

atQ-32

Battery

2.2-M

R-235

,0

:

*_- 9

n

!xl

aaa.fiarni

I

14 H-PC324C *
LM-324 ”

trDTHTTrU

R-233

180-k

.R-232

,2.2-M

To CPU Pin 31
via CN-3, Pin 11

A

R-230

564c

Replace R-235 with a 4.7-meg
resistor to raise the Low Batt
warning level. See text.

The heart of this circuit is IC-5, a basic
op-amp of the 324 type....common as
fleas on a junkyard dog. IC-5 is a 4-
section op-amp, only one of which is
shown above. The three remaining
sections are used for other purposes in
the scanner and are not relevant to this
discussion.

Op-amps are neat little chips with a
variety of uses, from basic amplifiers to,
in this case, voltage comparators! As the
name implies, this circuit compares one
voltage to another and makes a logical
decision accordingly. Specifically, a
preset reference voltage is applied to Pin
10, the non-inverting (+) input, while the
memory battery voltage is applied to Pin
9, the inverting (-) input of the op-amp.
In this specific configuration, the output
at Pin 8 will be zero-volts so long as the
battery voltage input is higher than the
reference voltage input. As the battery
weakens over the months, its voltage will
steadily drop until at some point, it falls
below the established reference voltage,
at which time the output at Pin 8 goes
high to Vcc or +8.3 volts.

The CPU senses the low and high logic,
and acts accordingly, or in this case,
does nothing while the reference is lower
than the battery voltage. When the
output shifts to a “high”, the CPU senses
it and turns on the Low Batt indicator in
the display and performs a repetitive
Beep until you change the battery. Now
let’s look in detail at how this happens.

The Memory Battery voltage feeds other
parts of the scanner, but it also directly
feeds the point shown in the diagram
above. A fresh 9-v battery will produce
at least 9.0 volts to this point. Now look
at the two resistors, R-235 and R-232,
each 2.2-MQ. Skipping the math for a
moment, because they’re equal, each
resistor will drop one half the batter
voltage, or 4.5-v each for starters. This
puts 4.5v at Pin 9 of IC-5. Now the
math, lest some thing the battery will
prematurely drain. Two 2.2-MQ resistors
in series with the battery are the
equivalent of 4.4-MQ. Using Ohm’s Law,
where current equals voltage divided by
resistance, we have 1 = 9* 4,400,000 or
0.000002045 amps, or 2-^ia. There’s
your answer: a 9-v battery can generate
2-ixa for a year or more. No sweat. The
idea was to get a sample of the battery
voltage at Pin 9 of IC-5. So one half the
battery voltage will always be at Pin 9.

Now let’s look at the reference circuit
We see where it is fed from the scanner’s
+8.3v supply through R-234 and R-233,
470-kQ and 180-kQ, respectively. Again
using Ohm’s Law, 8.3v * 470-k + 180-k
equals 12.8-jia. The voltage at Pin 10
will be the voltage dropped across R-233,
or: 180,000 x 0.0000128 = 2.3 volts.
This, then, is the reference voltage at Pin
10, which will not change.

Now it becomes clear as the battery
weakens from its starting 9 volts, exactly
one half the voltage, whatever it is, will

2/1/95-5:30 PM-Page !

be applied to Pin 9. When the voltage at
Pin 9 gets to be 2.3-v, the output at Pin 8
of IC-5 will shift from 0-volts to the
supply voltage of 8.3 volts, (low to high).
But wait!!

The CPU is a 5-volt device and would be
destroyed if punched with 8.3v logic.
Ahhhh, but that’s what R-231 and R-230
are for: protection! They form a voltage
divider, just like the previous two
examples, so we can once again use
Ohm’s law: I = 8.3 * 33-k + 56-k or: I =

8.3 89-k = 93-pa. The voltage that
gets passed on to the CPU will be the
voltage drop across R-230, or: 0.000093
x 89,000 = 5.2 volts. Accounting for
voltage drops within the chip, this will be
about 5.0 volts as a logic-high for the
CPU to turn on the Low Batt Indicator
and to sound the warning Beep.

That’s it, in its entirety, folks. Easy as
pie. And what’s more, the improvement
is now rather obvious. If the Low Batt
indicator doesn’t go off until the battery
has dropped to 4.6 volts (one half this is

2.3 volts, remember?), then that battery
is going to be mighty dead by the time
the alarm sounds. Would it be better to
have a little more warning in advance?

Easy as 1-2-3. We’ll keep the same
reference voltage of 2.3-v on Pin 10, but
change the circuit of R-235 and R-232 to
set the ratio that we want. My idea for a
better alarm point is 6.0 or even 7.0
volts....let’s say 7.0 volts. Ok, it will still
take 2.3v or less on Pin 9 to trigger the
alarm, but if we increase the value of R-
235 to drop more voltage than R232,
then that 2.3-v point will be reached
sooner than under stock conditions.
Let’s calculate how:

Assuming 7-v is applied to R-235, and
we want 2.3-v on Pin 9, that means R-
232 will have to still drop 2.3-v. That
leaves 4.7v to be dropped by R-235.
Current equals 2.3v -i- 2,200,0000 =

1.045-pa. That same current has to flow
through the new R-235, which equals
voltage divided by current:

4.7v -r .000001045, = 4.49-MQ Cool!
Let’s replace R-235 with a common 4.7-
MQ resistor instead of fussing with the
nonsense fractional value. Now let’s
finalize the calculations:

4.7-MQ + 2.2-MQ = 6.9-MQ total series
resistance. Now, when 2.3v is dropped
across R-232, 1.045-pa flows through it
as well as through the new R-235: The
voltage across the new R-235 at that
time will be .000001045 x 4.7 MQ or 4.9-
v. Finalizing, 4.9v in series with the 2.3-v
equals 7.2-volts, the point at which the
Low Batt Indicator will come on and the
alarm will sound! We already
determined that 4.5-MQ will trigger at
7.0-v, and obviously, 2.2- MQ triggers at

4.5-v, so there’s the pattern and the idea
for how to raise your Low Batt Warning
Indicator to a more reasonable level.
You could substitute a 5- MQ or 10- MQ
trimmer potentiometer for R-235 and
adjust your own trigger point. Got the
idea here? If not, ask me questions.

PRO-2004/5/6
MEMORY BATTERY
EXPLAINED

Here’s another one of those slick and
wicked circuits that may have escaped
your attention. It’s so simple that I
missed it for a couple of years. The
method by which the 9-v battery
preserves your programmable memory is
utterly wicked. Here’s its circuit from the
PRO-2005/6, and again, it’s identical to
that of the PRO-2004 though the circuit
symbols differ.

Ok, here’s the scoop. There are two
conditions that we have to analyze in the
below circuit. First, let’s assume the
scanner is not connected to any DC or
AC power. When this is the case, the
CPU and SRAM memory chip will lose
their memory contents unless +5v is
somehow supplied. No sweat, the 9-v
battery feeds through D-59 and R-247
into IC-9, a very special CMOS voltage
regulator that produces a steady, stable
+5v output over a wide range of inputs,
from about 5v to 15v or so. Hence, the
9v battery is more than capable.

The neat thing here is that IC-9 is so
special that it consumes almost no
current on its own, unlike most voltage
regulators that drop 2VS-3 volts and need
several milliamps just to operate. This
would drain the battery in no time. IC-9
is very special in that respect and can’t
be found on just any street corner. It
drops almost no voltage and consumes
only a few billionths of an amp. When

not operating, the CPU and SRAM
memory also consume only a few
billionths of an amp, so this may explain
why the battery can last for six months or
longer when the scanner is not connected
to power.

Continuing, resistors R-247 and R-256,
ten ohms each, do little more than serve
as current limiters to protect IC-9 in the
event of a short circuit somewhere in the
CPU area. These resistors are not
important in the rest of this analysis
because at the low currents we’re dealing
with, they drop almost no voltage.

This about wraps up the no-power
condition of the memory battery analysis.
Now, let’s look at what happens when the
scanner is plugged into either AC or DC
power, no matter whether it is turned on
or off.

A closer study of the schematic diagram
reveals that the AC power supply is not
switched by the on/off switch. If plugged
into 110-VAC, the internal power supply
is on full time and generating full DC
voltage of about 12-13 volts. This DC
voltage is switched, however, which turns
the scanner on and off. However, a
portion of that DC is fed to Q-33 to
generate a 10-volt output into D-56.

This same condition applies, even if AC
is disconnected and an external DC
supply is used. Q-33 is fed with full-time
power so long as the scanner is
connected to either AC or DC. This has
the effect of applying about +9.2v to the
cathode of D-56 and the anode of D-59.

Voile! This turns off any possible current
flow from the battery because the
cathode of D-59 becomes more positive
(+9.2v) than its anode fed by the (+9.0v)
battery! A diode is an OFF switch when
its cathode is more positive than the
anode (reverse bias). Summary: the
battery cannot pass current through D-59
when the scanner is connected to any
power! Yet, when it is disconnected, the

2/1/95 — 10:54 pm — The "World Scanner Report" © 1991-95; Volume 5, No 2; Page 2

anode of D-59 being more positive than
the cathode, will conduct thereby
allowing the battery to feed IC-9.

\

Concluding, then, when AC or DC power
is connected to the scanner, Q-33
provides a continuous feed to IC-9, which
in turn, produces the +5v “keep alive”
power necessary to preserve the memory
of the CPU and SRAM. If and when
power is removed from the scanner, the
battery instantly takes over the feed to
IC-9. The major player in this action is
D-59, which turns the battery feed on and
off as needed. Interestingly enough, the
PRO-2004/5/6 can lose both regular
power and the memory retention battery
supply for short periods (10-30 mins)
without loss of memory. I suppose this is
due to a number of capacitors in the CPU
+5v line which retain their charge for a

time. Thanks also to the extremely low
“deep sleep” current requirements of the
CPU and SRAM.

There really isn’t anything to modify in
this circuit, or that needs modification, for
that matter. I did replace the equivalent
of R-247 in my PRO-2004 with a 47Q
resistor because in my tinkering, I
inadvertently blew IC-9 a couple of times
and got tired of paying Tandy several
bucks a pop for the privilege. In my
opinion, 10Q is a bit too small. On the
other hand, I’ve not blown IC-9 since
those first couple of times, so maybe this
issue is not worth even a mention. It is
something you can do if ever IC-9 gets
popped for whatever reason. Otherwise,
this circuit is best left alone and allowed
to function as designed.

II • : f

The previous two circuit analyses literally
scream for an explanation of the power
supplies in the PRO-2004/5/6, so it may
as well be done here and now where it
fits best of all. The below diagram is a
schematic of the PRO-2005/6 power
supply, with superfluous circuits and
traces deliberately erased to simplify the
viewing and understanding of what's
going on here. The PRO-2004 and PRO-
2035 power supplies are very similar, but
circuit symbols will differ, and there are
minor differences here and there.

TO LOGIC
SECTION

* TORL 4
SECTIW

BATTERY

2 /U95 ~ 5:30 pm~ The "World Scanner Report" © 1991-95; Volume 5, No 2; Page?)

The AC Supply starts with the power
cord that feeds directly to T-801 with no
on/off switches in series. Thus, T-801 is
energized any time the scanner is
plugged into AC power. T-801 is a step-
down transformer, reducing 110-vac to
about 10-12 VAC. C-82 & C-81 are
noise and spike filters. R801 is a high
resistance shunt to chassis ground,
probably for static dissipation.

The low voltage AC is rectified into
pulsating 120-Hz DC by full-wave bridge
rectifier D-60, and filtered into a smooth,
ripple-free 12-13 vDC by C-238 (and C-
229). The path splits with one side going
to the On/Off switch and the other to the
emitter of Q-33 at the junctions of R-248,
C-246 and D-58. DC power is full-time at
this point where it is roughly regulated to
about 9.2-v by Q-33, D-57 and D-56 for a
feed to IC-9, the CMOS regulator for
CPU +5v already explained in a previous
section.

The External DC Supply begins with a
DC Adapter or power supply of your
choice connected to J-6. Despite
whatever the Owner’s Manual says, you
can provide anywhere from about 10-v to
15 volts DC at J-6.

L-58, C-237 and C-246 are noise and
spike filters while D-58 is for reverse
polarity protection in case you miswire
the plug for J-6. (Whew!) The center of
the plug should be (+) and the shell (-)
for whatever its worth. Like with AC, the
DC input circuit is energized any time a
source of power is connected.

Power Supply Modification #1: R-249,
as a current limiter, is a royal pain in the
ass and should be jumpered across to
eliminate it. You can also solder an
identical resistor in parallel with R-249, or
remove and replace it with a !4Q or IQ
resistor rated at 1-watt or even two watts!
R-249 at IQ rated at Vfc-watt, easily burns
out for the dedicated hacker. In the
PRO-2004, it's R-256 and in the PRO -
2035 , it's R-223.

A few punches on the calculator shows
that R-249 will burn
up with greater than
700-ma. The normal
current drain of an
unmodified PRO-
2004/5/6 is right at
350-400 ma. Cool.

But when an LED S-
Meter is added and
not too many more mods, we’re pushing
that 700-ma break point. Some of my
TurboWhoppers draw upwards of 1-amp
or so. Back in my bench repair days, I
found R-249 burned up on occasion in
some scanners for no apparent reason.
It’s best to modify R-249 as discussed
and get it out of your hair.

Power Supply Modification #2: The
dedicated hacker will run into all kinds of
power supply problems in time, so I
always recommend removal of the AC
supply altogether and running strictly
from a source of external DC at J-6.
Remove T-801, the AC power cord; and
R-801. You’ll end up with lots more “real
estate" for other mods, and your scanner
will run cooler by a substantial margin.

Continuing .The outputs of both the

AC power supply and the External DC
feed path meet at a common point in the
scanner best described as the junctions
of Q-33, R-248, C-246, D-58, C-238, and
the hot side of SW-801, the On/Off
switch. Basically, the scanner doesn’t
care which feed you choose because it
needs a very uncritical range of lOv to
15-v to operate to precision perfection.
This is possible thanks to the several
sub-power supplies that we’ll analyze in a
moment.

The +12v feed goes through SW-801, the
On/Off switch, and then through another
current limiting resistor, R-229, a 2.2Q
blue colored resistor rated at 1-watt.
This could be a bit underrated for super-
hacked scanners, but I’ve never seen one
burn up, even under the heaviest loads,
so there’s no reason to replace R-229 at
this time.

The switched end of R-229 (left end ,
closest to Q-32), makes for a great place
to tap a source of +12v for mods and
hacks. It stands up on raised legs and is
very accessible. You can tap +12v from
the other end of R-229, too, but that
needlessly draws more current through
the resistor, so take your +12v power
from the switched end.

The ON/OFF Switch is a physical part of
the Volume Control, but has no other
relationship to it. A gray cable with two
wires runs from the switch contacts to
the main receiver board and terminates
at CN-8. The On/Off switch switches low
voltage DC from either the AC supply or
the External DC feed. Switched DC goes
on to IC-7, IC-8, Q-32. the +30v supply
and the Hold circuit, all discussed below.

The Regulated Sub-power Supplies
are uncaring of their input voltage levels
within limits of reason and regardless of
the inputs within that range, their outputs
are fixed and stable. Basically, any feed
of 10-16 volts will be just fine for any of
these sub-supplies. There is only one
power feed in these scanners that is
subject to variation of input, and that’s
the +12v feed to IC7, the Audio Power
Amplifier chip, which really doesn’t care
what its fed with....from a range of 8 to
16 volts, it works just fine. Therefore, the
exact DC feed voltage is not really
important so long as the feed is capable
of generating the current we need, which

is about 400-ma for a stock scanner and
upwards of 1-amp for us hackers. Your
external DC Supply or Adapter should
be rated at 12-14 volts at one amp, at a
minimum. Unregulated will be ok.

The +12v common feed from either the
AC supply or the External DC supply
goes no where else, aside from the Audio
Amplifier, and to the inputs of the several
sub-supplies that we’ll discuss next.

The +8v Regulated Supply is the
predominant provider in the PRO-
2004/5/6 and PRO-2035. +12v feeds the
collector circuit of Q-32, which is biased
at its base by zener diode, D-54 to
producing approximately +8.3v at the
emitter of Q-32. Almost all the analog
electronics in these scanners are
powered from the emitter of Q-32. The
specified voltage of +8.3 can vary a lot
from one unit to the next, and I’ve seen
as low as +7.8v to maybe +8.5v. This is
rather odd, in my opinion, because the
critical receiver mixers and RF front end
can vary in performance over this voltage
range. +8.2v seems optimal, but it’s not
often seen without intervention. See the
end of this article for a modification that
allows you to optimize the +8v supply for
your receiver. The +8v supply produces
about 300-ma in most scanners. Q-32 is
a TO-220 style NPN power transistor
mounted on the receiver’s chassis next to
IC-8. A lot of our mods and hacks use
+8v, so it won’t hurt to solder a strip of
PinLine sockets to the emitter of Q-32 for
easy access to the +8v supply.

There are two +5v regulated supplies

in this scanner series, the first of which is
IC-8, a standard TO-220-style 3-port
7805 regulator, mounted and bolted to
the receiver’s chassis for heat sinking.
IC-8 is fed directly from the +12v line and
outputs a constant, regulated +5v for
most of the digital circuits in this scanner
series. Since modern digital electronics
are mostly CMOS, current requirements
are very low, and in fact, in a stock
scanner, IC-8 produces less than 100-
ma. This is great for us, since a 7805
regulator is easily capable of 1-amp or
so, and most of our mods and hacks
require a source of regulated +5v. It
won’t hurt to solder a strip of PinLine
sockets to the Out lead of IC-8 for easy
access to the main +5v supply.

The second +5v supply is IC-9 and has
already been discussed earlier in this
issue. There is no need for hacker use of
this +5v source and it should not be
tampered with under any circumstances.

The +30v Supply is a real oddity in this
modern age of low voltage systems, but
something in the PLL section needs 30
volts. The +30v supply is fed from the
main +5v supply to one end of R-219
where it goes into the basic "chopper”

p = i 2 r

— watt = I 2 x IQ
2

I 2

V7=VJ

I =.707 amps

2/1/95-5:30 PM- The "WorldScanner Report" © 1991-95; Volume 5, No 2 ; Page A

circuit of Q-24, Q-25, and T-9, where the
+5v DC is chopped into a pulsating DC;
stepped up by T-9; to about 30-vAC;
rectified and regulated by D-51 and D-53,
and filtered to a smooth 30-vDC by C-
215, R-215, and C-214. That’s all that's
worth telling about the 30-v supply. It
has no interest to us hackers and it
should not be tampered with under any
circumstances.

The “Hold” Circuit isn’t really a power
supply, but there’s no good subject area
to tell about it anywhere else. Since it’s
located in the power supply area of the
schematic, we’ll dissect it here.

Let’s see what this sucker does before
drawing any conclusions. Unswitched
(continuous) +12v feeds the Hold Circuit
at D-55 which with R-246, R-245, and C-
244, forward biases Q-31 into conducting
and driving its collector low. This “low”
appears on the base of Q-31 to turn it off,
where +4.4v then appears on the
collector. This 4.4v can loosely be
referred to as “+5v” high logic, which
becomes pertinent as we follow the path
from the collector of Q-30 to R-238 and
the base of Q-29. This “high” appears on
the base of Q-29, thereby shutting it off,
making a “low” appear on its collector.
Following the collector path of Q-29, we
find that it goes to CN-3, Pin 9, where it
is labeled “Hold”. Huh?

Ok, so we follow that path onto the
Logic-CPU Board where it goes to the
CPU, Pin 17. Nothing else in the Service
Manual is said about this “function”, but
we can make some educated guesses
after one more analytical effort.

Since continuous +12v feeds this Hold
function, let’s see what happens if power
is removed from the scanner. In that
case, Q-30, 31 and 29 cannot possibly
conduct. But lo! The memory retention
CPU +5v from IC-9 will place a +5v
“high” at CN-3, Pin 9 via R-236, just the
opposite from the low that is normally
there when the scanner has any power
applied to it!

Aha! My conclusion is that when power
is removed, this +5v high at CPU Pin 17
causes it to go into “deep sleep " mode
thereby minimizing the current required
from the Memory Retention Battery. Not
exactly a power supply, this "Hold”
function, but now you know ail about it.
I’d leave it alone, if I were you. It offers
nothing of interest to the hacker.

This concludes our first effort at circuit
analysis of a popular series of scanners.
If you have questions or if you want to
see other analyses, then fire away. I’m
your analyst. Just read page 1 in this
issue first, and make sure I have the
Service Manual for your scanner. I have
many Realistics and a few Unidens.

900 MHz CORDLESS PHONE FREQS

The Jan-Feb 1995 issue of the “ American
Scannergram ” shows the 900 MHz freqs
used by Panasonic and Radio Shack
cordless telephones. Apparendy there is
no official band plan because as you can
see, the only similarides are the band
edges and 30 KHz spacing. 900 MHz
phones from other manufacturers are
reported to differ as well.

Panasonic

Radio Shack

Ch

Base Handset

Ch

Base

Handset

mm

.926.100

wm

902120

mmm

02

mmm

926. ISO

mm

902.160

mmm

mi:

mmm

04

926.190

04

902.210

926.210

06

926.220

05

902.240

926.240

06

902.250

926.250

06

902.270

926.270

m

mmm

»

m

.926.310.

mi

mmm

69

mi

902,360

926.360

EM

902.370

926.370

m

902.390

926.390

11

902.400

11

902.420

962.420

12

902.430

926.430

12

902.450

926.450

mm

14 v

902 460
902-490

mmsm

WMMSm

m

ii

la

926.480

926.510

m g

902,520

926.520

m

902.540

mmm

16

902.550

926.550

16

902.570

926.570

17

902.580

926.580

17

E2EI

18

902.610

926.610

18

902.630

926.630

mm

mi

mmm

mmmi

m

902.670^926^70

m&mm

;926;690

mm

mi

rn/mm

wmm

22

902.730

926.730

22

902.750

926.750

23

902.760

926.760

23

902.780

926.780

24

mm

mm

902.790

SWSM20

mmm

926.790

mmm

936.8S0

24

wm

mm

902.810
902.840 .
902.870

926.810

926 840

926870

2 m

926,880

mm

mmm

28

902.910

926.910

28

902.930

926.930

29

902.940

926.940

29

902.960

926.960

\EM

WJM

902.990

926.990

32 -

BSi

mi

WwM\

mm

moeo

mmmi

mi

W?mm\

34

927.090

34

903.110

927.110

35

903.120

927.120

35

903.140

927.140

36

903.150

927.150

36

903.170

927.170

mm

mMM

.927,180

mm

mmm

mmm

wm

mm

903.210

903.240

ipii

38

Mi

mmm

.mam.:

927-23Q

927.260.

40

903.270

927.270

40

903.290

927.290

41

903.300

927.300

41

903.320

927.320

42

903.330

927.330

42

903.350

927.350

mm

mmm

mi

ftgasg;

gill

mm

903,390

mmmi

mm

mmm

mm

46

903.420

903.450

927+420 .
927.450

mm

46

903,440

903.470

927.440

927.470

47

903.480

927.480

47

903.500

927.500

48

903.510

927.510

48

903.530

927.530

49

wm

:903.540

903.370

; mmm

927.570.

mm

mm

903.560

903,590

927.560

927.590

mm

903.600

mmm

mm

903.620-::::

927,620

52

903.630

927.630

52

903.650

927.650

53

903.660

927.660

53

903.680

927.680

54

903.690

927.690

54

903.710

927.710

mi:

903,720

927.720

mi

mmm.

927.740

mi

903,750

927 750

mi

mmm

927:770

lii&i

58

903.780

903.810

927.780

927.810

mi

58

903.830

927,800

927.830

59

903.840

927.840

59

903.860

927.860

60

903.890

927.890

Given die apparent hodgepodge freq
assignments for this band, it’s probably
best searched in 5 KHz steps.

The “ American Scannergram” is the
official publication of die All Ohio
Scanner Club, 50 Villa Rd;
Springfield, Ohio, 45503-1036. The
“American Scannergram ”, while

definitely focused on the state of Ohio
and surrounding areas, is a nicely
assembled and edited newsletter of wide
appeal on the total spectrum of scanning.
Its main appeal seems to be local
frequencies and radio activities, but its
also big on equipment reviews, scanning
techniques and principles. It’s probably
a “must” for the library of the compleat
scannist. The motto of the AOSC is,
God We Trust , All Others We Monitor

Ill#:. *111®ATE- .1(11

The PRO-2004 was replaced by the
PRO-2005 in May, 1990. Radio Shack
supports a product for five years after
discontinuance. The “ Cinderella Hour •”
is coming up fast. In fact, reader Bob
Horvath reports Tandy is out of stock on
the PRO-2004 Electroluminescent Panel,
part # GE-85D-6067 given in WSR,
V1N2P7. I’m not sure the bewitching
hour has hit yet because I have been
using an updated part number for a
couple of years now: GE-86D-6011

But, update your PRO-2004 Service
Manuals on page 53, Item #43, to show
this new part number. While you’re at
it, it would be a good idea to order a
spare EL panel or two, perhaps a new
front panel, metal case and keyboard
cover, and even a whole new keyboard.

The below PRO-2004 items get the most
wear and tear and will be impossible to
find when Tandy cuts support of the
PRO-2004. Tandy Parts: (800) 442-2425

EL Panel
Escutcheon Assy
Cabinet

Panel, Keyboard
PCB Assy, Keyboard
Knobs, Vo I & Squelch
Knobs, Dimmer & SSq
Antenna, Telescopic
Vo I & Switch Ctrl
Squelch Ctrl

GE-86D-6011
GA-86D-6385
GE-86B-6360
GE-86D-6359
GA-86D-6320
GE-86D-6356
GE-86D6357
GE-86D-6519
5M1411-50KA-20A
K1611008TE-10KC-20

PRO-2004 Service Manual 20-119

Refer to the service manual for anything
else you might want to stock up on and
order NOW or forever keep your peace!

2/1/95 - 5:30 PM~ The "World Scanner Report" © 1991-95; Volume 5, No 2; Page 5

BC100XLT/200XLT
NiCd Battery Replacement

‘ByQreg Strauss

I've had my Uniden BC 100XLT for
about 5 years, and the NiCd pack finally
went out. So I called Uniden Parts and
they wanted $37.00 for a new battery
pack when all I wanted was the NiCd
cells from the inside. Uniden won't sell
the NiCd’s separately. I thought that it
would be the cheaper route to go by
soldering the NiCd’s in myself and not
having to buy the whole pack (BP205).

I looked through some electronic supply
magazines for the replacement part
(Sanyo Model #6N-550AA, 7.2V,

600mAh) with no luck. Then I opened
my Radio Shack catalog and found a
cordless phone replacement NiCd pack
(Cat# 23-193). This pack consisted of
only 3 AA NiCd’s at 3.6 volts but at
650mAh, which is 50-mAh better than
the original. I bought two of these
replacement packs from Radio Shack at
$9.99 each for a savings of $17.00. Here
is what I did to polish off the job:

1. Disconnect power supply from rear.

2. Slide the battery pack off the bottom.

3. Remove the two screws from the
bottom of the battery pack.

4. Slide the front panel off of the battery
pack. Be sure to pull the front panel
straight off making sure you do not
break the two top tabs.

5. Slide the battery pack out of the case.
(The 6 AA NiCd battery pack is
encased inside heat shrink wrap,.)

6. Cut the two wires as close to the
battery as possible. (I kept the wires
connected to the printed circuit board
because it looked even more diffi cult
to get that baby out)

7. I removed some of the adhesive
backed cushioning from the inside of
the battery pack to make room for the
new batteries.

8. I took the two new battery packs and
wired them in series, so I had a
positive and negative lead left.

9. Now the old battery pack end view
looked something like this:

with the batteries staggered. Keep
this in mind when placing the new
batteries in the case.

10. Now this is the tricky part. Look at
the inside of the battery pack lid.
You will notice three round shaped
tabs that were used to hold the old
battery pack in place. You will need
to trim these down in order for the
new NiCd’s to fit I used my wire
cutters which worked fine.

11.1 connected and soldered the positive
and negative leads and used heat
shrink to cover them.

12. Now remember the note in 9. You
will need to place the separate NiCd
packs in the case as such.

13. Things may fit a little tight but it will
work. Just be careful when replacing
the lid back on the pack. I used some
heat shrink to hold the new NiCd’s
together but it was to big for the case.
So I used a piece of tape to hole them
together.

I charged the new battery pack for 14
hours and had an 11 hour use time. Not
bad for a little work.

Editors Comments : Nice piece of work,
Greg, and very inventive! I included the
BC-200XLT in the title of your article
because the battery packs are the same,
and the radios are mechanically the
same for all practical purposes. Your
procedure will generically work for most
any “sealed” NiCd pack, too. For those
who want to save even more bucks the
individual cells shouldn ’t cost more than
about $2 each, if you can find them. It
might also be possible to beef up the
pack up even more with use of nickel-
metal hydride cells or heavy duty NiCds.

Good places to start the search for
individual replacement cells include:

Alexander Batteries (619) 480-4445
Sanyo Energy Co (619)661-6620
Metro West (708) 354-2124

Note thatMetroWest was big on supplies
for the BC-100XLT and 200XLT,
including a 1000-mAh rechargeable
pack. I haven't heard anything from
them in a long time and they may now be
out of business. Something to check.....

Also note that any beefing up of the
NiCd cells must be accompanied by a
beefed up recharger. The stock
recharger may be fine for 50-ma more
like Greg’s, but any more than that, and
we have to redesign some of the
charging circuit for higher current.

FROM THE REAPERS

FINDING THINGS IN PRQ-2006

From: Thomas Nichols, Indianapolis. IN

Hello, Dr. Rig. In regards to headphone
audio for the 2004 and 2005 (Book #1,
Mod #8, page 103), my 2006 has black,
white and gray wires to the headphone
jack, but no ground lug on jack, nor
could I find the 270 ohm resistor.

ED: In the PRO-2006, the black (middle)
wire is the ground wire that runs from
the shell of the head-phone jack to pin 3
of CN-6. R-228, the 270f2 resistor, is
physically connected between Pin 3 of
CN-3 and ground, but it’s a chip resistor
located on the bottom side of the main
receiver board between C-222 & C-226.
You do have the Service Manual, right?

Also, on 2005 squelch improvement, I
couldn’t find R-152 on my 2006. On the
2006 there is a metal sheet (frame) with
a PC board mounted on it covering the
bottom where the IC-2 is mounted above.

ED: R-152, 33-kQ, is a chip resistor
physically installed between Pin 12 of
IC-2 and Pin 1 of IC-10 on the bottom
side of the main receiver board. There
is an opening in the chassis nearby
where you can access R-152 at an angle .
The alternative is to remove the main
receiver board from the chassis. On the
other hand, IC-10 is a new addition to
the PRO-2006 that eliminates the need
for a Squelch mod. This has been
treated in back issues of the WSR.

Also, is there another BFO for mounting
inside the set?

ED: Not sure what you mean. There are
no BFO *s for the PRO-scanners, period.

Do you know about the new BC-9000?

ED: It’s a piece of junk with all its bells
and whistles coming from firmware; not
hardware. Firmware is a cheap way of
making a scanner (or other electronic
equipment) look great. Caution advised!

CALLER ID & SCANNERS ?

From: Robert Pyle, Miamisburg, OH

Is caller I.D. data transmitted by the base
of a cordless telephone? Is it possible to
connect a caller I.D. display to a 2006?

ED: 1 don’t know much about CID because
California won't allow it. People's rights
here are subsidiary to the rights of Big
Business, Government, and special interest
groups, including all minorities and
politicians. Some are more equal than others.

2/1/95 ~ 5:30 PM~ The "WorldScanner Report" © 1991-95; Volume 5, No 2; Page 6

IMPOSSIBLE CELLULAR MODS

From: Mrs. Gary Criblev, Thomaston, CT

We have a PRO-2030 scanner. On
Christmas day my husband wanted to
restore cellular to our new scanner. He
followed your instructions in V3N9, (Oct
’93) but there is ng L201 jumper! Is
there another modification for the newest
PRO-2030? If so, could you put it in
your next issue of the WSR. Thank you

ED: Either it's there and you haven't
found it, or else you bought that scanner
AFTER March, 1994, when it became
illegal to sell cellular-capable scanners.
Existing stocks could be sold, but it's
likely that Radio Shack pulled them or
sold out before the deadline. New
models imported or manufactured after
3/94 cannot be "easily modified", and to
the manufacturers, that means
impossible. \Fraid you 're outa luck.

From: David Cobb, Smithfield, NC

Bill: I recently tried to unblock cellular
coverage on a PRO-2026 AND A PRO-
2030. I have done this before, but on
these at the L201 location there was
nothing but two empty holes in the
circuit board. CAN YOU HELP ME? If
you know any other way to restore
cellular on these two units, please let me
know. (Units were purchased 12/94).

ED: See above. You 're S.O.L., too.

COST OF BLUE LEDs DROPPING
From: Fred Jacobson, Wenatchee, WA
The price of Blue LEDs is getting lower.
Check out Digi-Key’s newest prices!
800-344-4539

DigiKey Blue LED Prices

Quantity^ 1 10 100 500

100CR-ND T VA diffused .88 7.83 60.75 243.00
101CR-ND T-l>/4 clear .88 7.83 60.75 243.00
102CR-ND T-l diffused .88 7.83 60.75 243.00
103CR-ND T-l clear ,88 7.83 60.75 243.00

No min order, $5 handling charge on
orders less than $25.00. Foreign orders
add $5.00. No shipping US & Canada.

ED: Great Boogley-Woogley! I'll say
the price has dropped! Thanks!

Service Manuals& BC-2500XLT
From: Don Alesch, Jr., Menasha, WI
Dear Bill, Just a quick note on your
response to Mr. Schlegel on page 6 of
V5N1. I did send you a Service Manual
for the BC-2500 back in Sept 6 93.
“Anyone” learned to teach this thing any
tricks such as Mr. Schlegel requested?

ED: Much of the time we 're sent partial
and/or poorly reproduced copies of
service manuals which get promptly
flung without hesitation into the nearest
circular file. I retain and study only full
and complete copies in good, readable
condition. In any event, I know little of
the BC-2500XLT and have no idea if
anyone else has probed it. It would seem
not; else I'd have heard about it....I'm
all ears to that sort of thing. ©

EXTENDED MEMORY MODS

From: Todd Penney, Nova Scotia Can

one buy a preassembled, pretested 6,400-ch
extended memory board with the KMBC
MOD-28 for the PRO-2006. If so, what
would be the cost of this board and would
Vols 1 & 2 of the Scanner Modification
Handbooks be adequate for the installation?

ED: At various periods of my Life, I sat
down and made up reassembled circuit
boards for the various mods. I've been
so busy over the last couple of years that
this has had to take a back seat and none
are presently available other than the
CE-232 Interface and the MOD-44
Data/Tone Squelch. However, I have
refined the Extended Memory mods to
eliminate the need for boards and most
wires altogether. This has been
thoroughly documented in back issues of
the WSR. The mods in my books are
certainly more than adequate if you want
to go that way; otherwise, research the
WSR back issues and apply my new
techniques for an incredibly easier job of
most any Extended Memory mod.

Within each of the 16 switchable blocks
can you operate your scanner as a normal
scanner of 400 channels with 10 banks?
i.e. switch into Block 3, have only banks
4,5, & 9 on and have 50 of 120 channels
locked out?

ED: Indeed! That's part of what my
Extended Memory Mods are all about!
The 16-Block, 6400-ch Mod is like
having sixteen scanners lined up in a
row with one useable at a time.

PS What’s this about 25,600 channels?

ED: That's what I mean about the back
issues of the WSR! Try 64-Blocks of
400-channels each for less work and
equal or slightly higher cost than the old
MOD-16 in my books! It's all in the
back issues and cannot be repeated
again soon for obvious reasons. The
new techniques call for surface mount
memory chips instead of DIP types!

2/2/95 ~ 12.17 am ~ The ” World Scanner Report" © 1991-95; Volume 5, No 2; Page 7

CQNfcieEH^liSUBS^^

NAME:

USA RATES shown: Canada add 15%; Other Foreign +25%-surf/+50%-Air

$

STREET

1991 (1st Year, Jan-Nov/Dec)-10 ea $20.00

1992 (2nd Year, Jan-Nov/Dec)-10 ea $21.00

1993 (3rd Year, Jan-Nov/Dec)-10 ea $23.00

1994 (4th Year, Jan-Nov/Dec)-10 ea $25.00

$

$

CITY: STATE: ZIP:

$

$

Work Ph: ( ) - Career or

1991-94 (All the above) - 40 ea $79.00

$

Home Ph:( ) - Profession

lliiiiii

TYPE OF SCANNERS »

& Other Radios »

Half Year 5 ea $15.00

One Year lOea $25.00

$

$

METHOD OF Check Cash M.O. Visa MstCard COD (+$8.50)
PAYMENT » □ □ □ □ □

Amount Enclosed

$

Two Years 20 ea $45.00

.

$

Credit Card

Acct No:» -

Amount Charged
$

Scanner Mod Hndbk, Vol-1: $17.95 + $4.00 S&H *
Scanner Mod Hndbk, Vol-2: $17.95 + $4.00 S&H *

$

$

Name of Expiration /

Issuing Bank Date: /

Scanners & Secret Frequencies $19.95 + $4 S&H *

* Canada US$9 S&H; Other Foreign US$9 S&H; all add extra for Air

$

$

Signature Required (for credit card purchases)

X

CE-232 Interface Kit $194.95 + $5 S&H; All Foreign add 25%-surf

Hertzian Intercept BBS Subs: $8/mo $15/3-mo $25/6-mo $40fyr $75/2-yr

HOBBY RADIO BUYER’S DIRECTORY $14.95 ppd. surf

Calif residents: Salaa Tax - 7.0% on all orders except WSR subs

$

! VISA

$

$

What else to tell us?

$

US FUNDS PAYABLE TO; CQMmrtmm&tgtoMtin#

L

$

STOCKING UP ON PARTS
From: Tony Thornton, Mize, MS

Hi Bill & Cindy; After Getting my PRO-
2006 and using it for a while now, I can
see why so much praise has been
bestowed upon it in the scanner
community/press. I chose the 2006 over
the 2035 although I will most likely get a
2035 later.

ED: See the recent back issues where
we covered the PRO-2035, a clearly
worthwhile scanner. I don’t know that it
beats the 2006, probably not, but it still
has advantages, some pretty powerful.

But, I want to continue to use the 2006
for many years so this leads to the reason
for my letter. Could you, during the next
year when you have time & space in the
WSR, list some recommended parts to
buy and “stock” for the PRO-2006. I am
concerned that parts might be
discontinued in the future and some of us
might want to get some spares to keep on
hand. You know, the stuff that is only
available from Tandy.

ED: See my brief on page 5 this month
for the PRO-2004! What timing! The
PRO-2006 should be supported by Tandy
for another 4-yrs, so there's no hurry,
but your concern is certainly valid. Use
my list for the PRO-2004 as a general
guide and translate the part numbers to
those for the PRO-2006 and you 'll have
ample preparation.

EL PANEL CONSIDERATIONS

Does age still kill the display even if the
light is seldom used?

ED: Darn good question, and I don't
know for sure. The EL Panel is electro-
chemically active when 80-110 VAC is
applied to it. Chemistry is one of those
areas where age & environmental
factors clearly play a role. I would
advise spare EL Panels to be seal-
wrapped and stored in the refrigerator,
but there's little you can do for the one
in the scanner short of keeping it off.

After seeing how they illuminate the
PRO-2035's LCD Display with LED's, I
may try to work up a similar scheme for
the PRO-2004/5/6 and 2021/2022, etc.
Shouldn't be difficult, but we need a
source of frosted glass or plastic in
order to make it feasible . The LCD
Display module is clear, as you may
know. Bright LEDs behind clear glass
would be obnoxious without something to
diffuse and spread the light a little.

List some tips to make the 2006 last
forever, (joke! ©)

ED: Serious business, if you ask me.
The single best thing you can do is use
12-14 vDC from an external power
supply and don't use the AC supply.
Otherwise, keep it clean and cool. It
should last a long time and at least until
its been antiquated by the next wave!

Also the PRO-43 seems to be less
sensitive than my other scanners. Can
VHF low band sensitivity be improved?
By me? If not, is there a technician I can
send it to that might be able to help it a
little? Other than this, I love the PRO-
43 because what you hear is really there.
Thanks for a great newsletter and keep
those mods coming.

ED: There's nothing you can do unless
to undo something you may have done to
wreck the sensitivity. Did you resolder
the antenna wire inside after doing the
cellular and other mods? Not doing so
will be a killer on the sensitivity. There
may be a way for you to perform a basic
realignment with the aid of an S-Meter,
but I haven't transcribed the procedures
into layman's lingo yet and there has
been no demand. If your PRO-43 isn V
seriously hacked, I'd suggest sending it
to a Radio Shack service center for an
alignment. The antenna is important,
though, and one cut for VHF-Lo will do
more than anything to snag those elusive
signals that you think you 're missing.

NEXT ISSUE WILL BE LATE I

Normally, we take June and December
off. This one time, we're taking off in
March. V5N3 will be mailed in late
March or early April so as to give me the
much needed time to finish my third
book The Ultimate Scanner . We’ll be
back on schedule by July with V5N6
mailed in that time frame. We won’t
take May off as is our usual custom. In
no case will you miss any issues.

| MY BOOK IS PROGRESSING I

But the graphics and detail are incredibly
slow and painstaking, much slower than for
my first two books where quality was not the
highest item on that publisher’s list of
priorities. I have a new publisher now, who is
the cat's meow for quality and doing things
right. Since he’s that way, I can be no less so.
Good things come in due time. Watchl ©

2/1/95 - 5.-47PM- The " World Scanner Report" © 1991-95; Volume 5, No 2; Page8

COMMtronics ENGINEERING'S
mSCMim REPORT”
FO BOR 262178
SAN DIEGO, CA 92196-2178

950128V5N02P10

Remember - Next Issue Will Be Late

o TOCTT1?

+ New: Scanner Circuit Analysis! PRO-2004/5/6 Low Batt Circuit Explained
+ PRO-2004/5/6 Memory Battery Circuit Explained
+ PRO-2004/5/6 Power Supplies Explained ~ Power Supply Modifications
+ 900 MHz Cordless Phone Freqs for Panasonic & Reaslistic
+ UPDATE: PRO-2004 Parts May Soon Be Gone! ~ BC-100/200XLT NiCd Packs
+ Finding tilings in the PRO-2006 ~ Caller ID & Scanners? ~ Impossible Cellular Mods
+ Cost of blue LEDs dropping ~ Note on Service Manuals ~ Exgtended Memory Mods
+ Stocking up on parts ~ Electroluminescent Panel Considerations
+ Next Issue will be one month late
+ My Book is Progressing